Diabetes has reached epidemic proportions in the United States, and now we know just where the disease it at its worst: in a cluster of 644 counties in 15 largely southeastern states, making up America's "Diabetes Belt."

Regional trends are often defined in terms of "belts." There's the sun belt, the corn belt, the bible belt, the rust belt, and dozens of others. Back in the 1960s, medical researchers identified several states with high stroke mortality as the "stroke belt", and now scientists have determined what parts of the country suffers from the worst rates of diabetes. Lead investigator Lawrence E. Barker explains:

"Identifying a diabetes belt by counties allows community leaders to identify regions most in need of efforts to prevent type 2 diabetes and to manage existing cases of the disease. Although many risk factors for type 2 diabetes can't be changed, others can. Community design that promotes physical activity, along with improved access to healthy food, can encourage the healthy lifestyle changes that reduce the risk of developing type 2 diabetes."

The researchers determined four key factors that distinguished the "diabetes belt" from the rest of the country:

1. Population of the diabetes belt counties contained substantially more non-Hispanic African Americans compared to the rest of the country (23.8% for the diabetes belt, 8.6% for the rest of the country).
2. Prevalence of obesity (32.9% vs. 26.1%) was greater in the diabetes belt than in the rest of the U.S.
3. Sedentary lifestyle (30.6% vs. 24.8%) was greater in the diabetes belt than in the rest of the U.S.
4. Proportion of people with a college degree was smaller (24.1% vs. 34.3%).

So where is this belt located? The 644 counties are centered mostly in the southeastern United States, and they're found in Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, and the entire state of Mississippi. Dr. Barker says that this knowledge will hopefully spur residents of the belt to be more conscious of their heightened risk and take greater steps to avoid the condition:

People who live in the diabetes belt will reduce their chance of developing type 2 diabetes if they are more active physically and, for those who are overweight or obese, if they lose weight. Taking these steps will eventually lower the prevalence of diabetes within the diabetes belt."